1. Field of the Invention
The present invention relates to an improved electrode structure of planar lamp, particularly to one, wherein an electrically-conductive element that traverses the bending channels of the planar lamp is adopted to increase the input area of the power output by the discharge electrodes so as to achieve the light uniformity of the planar lamp.
2. Brief Discussion of the Related Art
What the planar fluorescent lamp lays most stress on is to achieve the uniform distribution of light, and the operational principle of the conventional planar gas-discharge lamp, which is used as the backlight source, is that with an inverter providing the power, the fluorescent material coated on the light-emitting side is excited to emit light via the means of gas (usually an inert gas) discharging. For the similar technology, please refer to R.O.C. Patent Publication No. 521300 “Dielectric Barrier-Type Discharge Lamp With Support Element Between Bottom Plate And Cover Plate”. According to the electrode design, the gas-discharge lamp can be divided into the external-electrode type (referring to FIG. 1) and the internal-electrode type, wherein a closed cavity is formed between the top-layer glass of the light-emitting face and the bottom-layer glass of the light-reflecting face and the closed cavity is filled with a reaction gas, and wherein a support portion is usually formed in the cross section of the top-layer glass, and wherein a fluorescent material is coated on the internal surface neighboring the light-emitting face and a reflective material, which can reflect the light propagating downward, is coated on the internal surface neighboring the light-reflecting face; in the external-electrode type gas-discharge lamp, the electrodes adhere to the external surface of the bottom-layer glass and an insulating layer is coated over the electrodes; in the internal-electrode type one, the electrodes are disposed inside the closed cavity, and a support element is used to separate the top-layer glass and the bottom-layer glass. Once receiving the power transformed by the inverter, the reaction gas inside the cavity will discharge and emit the ultraviolet ray to excide the fluorescent material to emit light.
In the external-electrode type planar gas-discharge lamp, in order not to influence discharge, the reflective material must be very thin; therefore, a portion of light emitted from the fluorescent material is apt to transmit through the light-reflecting face, and the insulating layer has no reflective ability, which further induces the light to leak from the light-reflecting face more seriously; thus, the light efficiency is influenced. Furthermore, as shown in FIG. 1, in both the internal-electrode type and the external-electrode type, the electrodes are usually disposed in both ends of the planar lamp; as the electrodes of both ends of the planar lamp have many bending channels, a higher initial voltage for discharge is needed in the portions of the sharp corners of bending channels; however, the light in some portions is still dim as the distance between the electrodes is too long.